[solved] Basic layout question

If I got a very simple widget based application with just one button in the lower right corner, how can I tell the button to stay in the lower right position even if the window is resized.

In C#/Windows Forms, iOS, OSX you would tell the widget (which is called view there) to stay glued to the next thing that is right next to and beneath it.

In Qt there seems to be a complete different paradigm: layouts should be what I a looking for. But somehow I don't get the drift how to use layouts for this fairly simple task. I guess it's simple, my way just needs to be rewired for the new way of approaching layouts 8)
And yes, I've used the Forum search and Mr. Google ;-)